Historical questions on welding/fillet brazing/lugging steel frames
Scott Gordo
someone can pass a link along that would be great. I'm not an engineer
or metallurgist, so layman's language would be much appreciated ;)
Also, yes, tig welding vs lugging vs fillet brazing is indeed one of
those Holy War-sparking questions, so even though I expect it I'm not
trying to provoke it.
Were early solid bar frames welded or brazed?
Were early tubular steel frames welded or brazed?
If brazed, was it because steel wasn't as refined as today and became
brittle from the heat?
When did chromium molybdenum steel become the standard?
bjwe...@gmail.com
If you go way back into the archives of this group,
there is a lot of information, including knowledgeable
posts from Keith Bontrager, on lug brazing, fillet
brazing, TIG welding, and their effects on steel, heat
affected zones, and on the construction of lightweight
frames.
Welding can overheat the steel near the joint in a
thin tube frame - so you get a strong weld and a
weakened zone (the heat affected zone) right next
to the weld. So can brazing, if not done well.
TIG welding overcomes this when done well. So
before TIG welding was a common process, lightweight
frames were brazed and only heavy frames like Schwinn
Varsities were welded (because their heavier tubing
could take the heat).
http://www.sheldonbrown.com/varsity.html
Steels vary in their weldability and I don't know the
history of what steels were used for bicycles before
the introduction of high strength steels (Reynolds 531
was introduced in 1935, I don't know when 4130 chromoly
became common). IIRC, 531 is not recommended
for TIG welding, but 4130 certainly can be.
Of course 4130 existed long before TIG welding became
a common process in bicycle construction until the
late 80s or so. TIG welding existed before then, but
for whatever reason wasn't used in the bike industry.
Bontrager would probably say that the demands of
lightweight MTB construction speeded the adoption of
TIG welding. Anyway, the process became common
long after the weldable high-strength steel did.
Ben
Tim McNamara
<d7a25bd9-234d-45d4...@o14g2000vbo.googlegroups.com>,
Scott Gordo <blubb...@gmail.com> wrote:
> I'm sure this has been answered mightily in this group before, so if
> someone can pass a link along that would be great. I'm not an engineer
> or metallurgist, so layman's language would be much appreciated ;)
> Also, yes, tig welding vs lugging vs fillet brazing is indeed one of
> those Holy War-sparking questions, so even though I expect it I'm not
> trying to provoke it.
>
> Were early solid bar frames welded or brazed?
Yes. Forge brazed or forge welded, generally, as gas welding/brazing
tools were not widespread for much of the early history of bicycles.
Many of the early bikes were built by blacksmiths.
> Were early tubular steel frames welded or brazed?
Generally forge-brazed until gas-welding and brazing became widely
adopted. It's faster, cheaper and more accurate.
> If brazed, was it because steel wasn't as refined as today and became
> brittle from the heat?
That I do not know.
> When did chromium molybdenum steel become the standard?
Well, the standard for decades was Reynolds 531 which isn't really a
chrom-mo tubing, having no added chromium in the alloy (the proportions
of the alloying materials are 1.5% manganese, 0.25% molybdenum, 0.35%
carbon).
<http://web.archive.org/web/19980109144634/reynoldsusa.com/history/histor
y.html>
Chalo
>
> Were early solid bar frames welded or brazed?
That sounds like a question for Carl Fogel.
> Were early tubular steel frames welded or brazed?
For the most part, they were "hearth brazed" over open coal fires.
Some used lugs, while others were fillet brazed internally with brass
preforms and others were fillet brazed externally. In all cases,
hearth brazing heats the entire section of the frame relatively
uniformly.
> If brazed, was it because steel wasn't as refined as today and became
> brittle from the heat?
At the time of the first bike boom, arc welding was immature and
expensive, resistance welding was new, and gas welding or gas-shielded
arc welding had not yet been developed. Forge welding was well-known,
but it was weak, inconsistent, difficult to do, limited in the range
of forms it could join, and easily contaminated. Brazing was an
altogether better and much more widely understood joining method than
any type of welding before the advent of inert gas shielded arc
welding.
> When did chromium molybdenum steel become the standard?
I hope that someone here can fill us in on this.
Chalo
carl...@comcast.net
<chalo....@gmail.com> wrote:
>Scott Gordo wrote:
>>
>> Were early solid bar frames welded or brazed?
>
>That sounds like a question for Carl Fogel.
Dear Chalo,
Solid bar frames?
Must be some new-fangled technology developed after 1900.
The closest thing to a solid bar that I know of is the early cast
aluminum frame of the Lu-Mi-Num of 1893, but that frame was cast
hollow (the fork was cast solid).
The frames of early safety bicycles were brazed, as these books
detail--search for braze/brazing/brazed versus weld/welding/welded.
Burr, "Bicycle Repairing," 1896:
http://books.google.com/books?id=8tFk2_ekVa0C&printsec=titlepage
Pemberton, "Complete Cyclist," 1897:
http://books.google.com/books?id=hW8EAAAAMAAJ&printsec=titlepage
Garratt, "Modern Safety Bicycle," 1899:
http://books.google.com/books?id=NMgeFMDBE18C&printsec=titlepage
Hasluck, "Cycle Building and Repairing," 1900
http://books.google.com/books?id=4EsxXM90hDcC&printsec=titlepage
Cheers,
Carl Fogel
Chalo
>
> Chalo wrote:
> >
> >Scott Gordo wrote:
> >>
> >> Were early solid bar frames welded or brazed?
> >
> >That sounds like a question for Carl Fogel.
>
>
> Must be some new-fangled technology developed after 1900.
>
> The closest thing to a solid bar that I know of is the early cast
> aluminum frame of the Lu-Mi-Num of 1893, but that frame was cast
> hollow (the fork was cast solid).
>
> The frames of early safety bicycles were brazed,
I didn't assume Scott was talking about safety bike frames, but rather
about the backbones of velocipedes and high-wheelers, which often seem
to have a rectangular section that suggests they are solid.
Chalo
carl...@comcast.net
Dear Chalo,
As far as I know, wire-wheel highwheeler backbones are hollow,
regardless of section. They're usually gracefully tapered, too.
Inserting reinforcing pieces is common in restorations of badly
corroded highwheeler backbones.
When you get into pre-wire-wheel boneshakers, anything is possible,
including wooden beams. Some used solid rods, others used hollow
tubes. They only flourished for about a decade before evolving into
the highwheeler, an even shorter history than the highwheeler itself,
which lasted about twenty years.
Cheers,
Carl Fogel
Chalo
>
> Chalo wrote:
> >
> >I didn't assume Scott was talking about safety bike frames, but rather
> >about the backbones of velocipedes and high-wheelers, which often seem
> >to have a rectangular section that suggests they are solid.
>
> regardless of section. They're usually gracefully tapered, too.
> Inserting reinforcing pieces is common in restorations of badly
> corroded highwheeler backbones.
>
> When you get into pre-wire-wheel boneshakers, anything is possible,
> including wooden beams. Some used solid rods, others used hollow
> tubes. They only flourished for about a decade before evolving into
> the highwheeler, an even shorter history than the highwheeler itself,
> which lasted about twenty years.
Yes, when I go looking for examples of what I'm talking about, these
are the sorts of things I find:
http://www.sportsantiques.com/SFAntPost_06/CrusherBike.jpg
http://lh5.ggpht.com/_lLHZo4bfupo/SZSH3gq6nkI/AAAAAAAAAOQ/VUq9TpVWj-c/DSC00738.JPG
http://www.wundercam.it/wp-content/uploads/2009/04/29032009.jpg
http://farm2.static.flickr.com/1087/1247713948_33e044e2da_o.jpg
http://lh6.ggpht.com/_ZpIXo_pdEM8/Rwaeos61pjI/AAAAAAAAAEo/jD6cdDmZqXs/DSC00067.JPG
http://lh6.ggpht.com/_p7OQpUvpk2k/SQHzYkCOkZI/AAAAAAAAB-U/UPumJaVwX_Y/CA+Bicycle+Museum+October+2008+014.jpg
I doubt any of these date to later than around 1870. But they look to
have been made by blacksmiths rather than machinists.
Chalo
carl...@comcast.net
Dear Chalo,
Thanks, that's a nice selection of the pre-wire-wheel boneshakers. As
you point out, mostly solid frames (and all solid wagon-style wheels).
Blacksmiths could indeed make boneshakers, but most boneshakers were
mass-produced by small companies in the late 1860s and sold for what
were very high prices in that era.
The Price velocipede is a good example:
The Scientific American ran a fairly regular column about velocipedes,
which appeared after the Civil War in the US (lots of northern
machinists were looking for things to machine) and were mostly a fancy
big-city phenomenon, complete with riding academies and rental by the
half hour.
Here's one of the early columns, from 1868, which soon became titled
"Velocipede Notes":
Note the patents on the Hanlon velocipede, which was built by "Calvin
Witty, carriage builder, 638 Broadway, New York." By the late 1860s,
NYC carriage builders were considerably closer to machinists than to
Longfellow's village smithy under that chestnut tree in 1841.
The pedals alone were often trickier work than most blacksmiths would
attempt. Here's one of Pryor Dodge's gorgeous photos, the pedals of a
circa 1868 boneshaker:
http://i40.tinypic.com/jrqqn6.jpg
Cheers,
Carl Fogel
someone
> > Were early tubular steel frames welded or brazed?
>
> For the most part, they were "hearth brazed" over open coal fires.
> Some used lugs, while others were fillet brazed internally with brass
> preforms and others were fillet brazed externally. In all cases,
> hearth brazing heats the entire section of the frame relatively
> uniformly.
Without a gas torch it is difficult to get a fired hearth to evenly
heat the joints to achieve consistently good brazed joints. (so I've
been told). Bellows or a fan most certainly are needed. The addition
of a gas torch to a fired hearth is supposed to be the easiest
technique once set up. The gas from coal, I imagine would increase the
difficulty of brazing against using coke, the coal's heat out put is
hotter and variable.
Tim McNamara
<97131507-cfb1-41dd...@h23g2000vbc.googlegroups.com>,
someone <thirt...@live.co.uk> wrote:
I did some hearth brazing with a friend who has a hearth and blacksmiths
on his farm (he farms by horse and it turns out that you apparently
can't buy spare parts for a lot of his equipment, so he makes his own).
It was pretty fascinating- we used a penny as the brazing material, in
this case between a tube and a flat plate with some flux applied to both
surfaces. The assembly just sat there unchanged until quite suddenly
the penny melted, flowed into the joint and spread out a bit along the
flux, and then the assembly had to be lifted out from underneath. I
suppose for frame assembly by hearth brazing, one would wrap a loop of
filler around the joint and/or coil it inside the joint.
I can't remember if he used coke or coal- I recall some conversation
about anthracite versus bituminous while waiting for the penny to melt.
On the whole I'd say a gas torch is way more convenient- faster, more
accurate heat control, safer, cleaner. There's a lot of soot and
gaseous exposure with a forge- blacksmithing seems hard on the lungs and
eyes.
someone
> In article
> <97131507-cfb1-41dd-8f97-635ca9379...@h23g2000vbc.googlegroups.com>,
The brazing material is used in its raw form, spelter, not as rods.
It is mixed up with the flux.
>
> I can't remember if he used coke or coal- I recall some conversation
> about anthracite versus bituminous while waiting for the penny to melt.
>
> On the whole I'd say a gas torch is way more convenient- faster, more
> accurate heat control, safer, cleaner. There's a lot of soot and
> gaseous exposure with a forge- blacksmithing seems hard on the lungs and
> eyes.
The problem with a fuelled hearth is that when adding the air it is
quite easy to overheat the tubing when making a satifactory joint at
the lug. Using a fuelled hearth with gas/air torch means that the
hearth burn rate can be adjusted to keep the background heat low
enough to not damage the tubing but high enough all over to facilitate
the torch in filling a joint completely in a moment after the braze
becomes molten. The torch only needs to be applied to the lugs, the
braze is drawn through the joint and the frame removed to set. The
problem lies in the temperature control of the hearth. Modern day
probes may assist in this 'old' craft.
Scott Gordo
>
> - Show quoted text -
Wow. This thread has taught me a lot. I always assumed that 531 was
cromo. Sheesh. I'm 39, have had lots more bikes than years, yet I
don't think I'll ever stop feeling like a noob around here!
I'm going to try and compile the methods and dates into a cohesive
timeline.
--D-y
> For the most part, they were "hearth brazed" over open coal fires.
Mercian calls this "open hearth brazing":
<http://www.merciancycles.co.uk/craft.htm>
Just the one photo there. Can't tell for sure if the bricks are heated
other than by the hand-held torch.
--D-y
someone
There are no 'coals', so extremely unlikely. The 'simplicity' of the
oxy-acetyline setup in unskilled hands is what causes brittle fracture
of bicycle tubing due to the innapropriate application of fierce
heat. A wide difference in temperature between lug and tube will make
good joint penetration difficult. A gas/air mix has a lower heat
output per volume so the temperature rise is slower and even. A
larger flame also helps with even heating.
Chalo
>
> Wow. This thread has taught me a lot. I always assumed that 531 was
> cromo. Sheesh.
Manga-moly.
Chalo